* Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, it expands to a single
word with the value of each parameter separated by the first character of the IFS special variable. That is, "$*" is equivalent
to "$1c$2c...", where c is the first character of the value of the IFS variable. If IFS is unset, the parameters are separated
by spaces. If IFS is null, the parameters are joined without intervening separators.

So it is equivalent to all the positional parameters, with slightly different semantics depending on whether or not it is in quotes.